Incandescent lamp having an envelope with a cap formed on the base thereof to prevent axial moving relative to said cap



Oct. 13, 1970 A. s. VAUSE ET 3,534,217

INCANDESCENT LAMP HAVING AN ENVELOPE WITH A CAP FORMED ON THE BASE THEREOF TO PREVENT AXIAL MOVING RELATIVE TO SAID CAP Filed May 23, 1969 ARTHUR SAMUEL VAUSE G EORGE DOUGLAS SPARROW INVENTORS ATTORNEY United States Patent U.S. Cl. 313318 4 Claims ABSTRACT OF THE DISCLOSURE An incandescent filament lamp having an envelope closed with a wedge-shaped pinch seal and a cap disposed about the seal. Indents in the side Wall of the cap provide seating structures for the seal.

The present invention relates to the provision of cap connectors for the pinch sealed envelopes of lamps, such as, for example, fluorescent lamps, discharge lamps and incandescent filament lamps.

It has been proposed that lamp envelopes should be closed with a pinch seal through which terminal leads for connections to filaments or electrodes would be sealed. Such a pinch seal could be plugged directly into a socket thus dispensing with the need to seal a conductive cap onto the end of the envelope. However, the introduction of such a lamp would require replacement of all existing sockets by sockets adapted to receive pinch sealed lamps. This amount of obsolescence would not be acceptable in, for example, the field of domestic lighting, where it would involve the replacement of many millions of light fittings. It is however clear that considerable manufacturing advantages could be obtained if lamps were pinch sealed.

According to the present invention, a lamp comprises an envelope having a pinch seal at one end thereof, at least one terminal wire sealed through and extending beyond said pinch seal, a cap having a side wall disposed about said pinch seal, indents formed in said side wall to form seating structures for said seal, said terminal wires being connected to said caps whereby said seal is held against said seating structure and said envelope is prevented from moving axially relative to said cap.

In a preferred form of the invention an incandescent filament lamp includes an envelope formed with a wedgeshaped pressed pinch seal the thin end of the seal being the end remote from the filament, and a cap the side walls of which are formed with indents to form seating structures which co-operate with the sides of the wedgeshaped seal to seat the envelope in the cap.

Advantageously, the pinch seal tapers on one or both sides from its centre portion towards one or both of its edges.

The seating structures may include portions of a shape complementary to the shape of the seal whereby a face to face contact between the seal and the seating structure is maintained when the envelope is seated in the cap.

The invention will now be described, by way of example with reference to the accompanying drawings, in which:

3,534,217 Patented Oct. 13, 1970 ice FIG. 1 is a side elevation of an embodiment of the invention,

FIG. 2 is a section of the lamp shown in FIG. 1 along the line II-II of FIG. 3, and

FIG. 3 is a section of the lamp shown in FIG. 1 along the line IIIIII of FIG. 2.

The lamp shown in the drawings comprises a glass envelope 11, the bulbous portion 12 of which surrounds a filament 16. A supply of electrical power is coupled to the filament 16 via two terminal wires 15 that are sealed through a wedge-shaped pinch seal 14. The thin end 25 of the seal is then end remote from the filament 16. The seal 14 also tapers from its centre portion 26 towards both of its edges 27. The glass envelope 11 is seated in a cap 17 which, in this embodiment, is an Edison screw cap. The end of the cap 17 is sealed by a plug 33 of vitrite and, one of the terminal wires 15 passes through an opening in this plug and contacts a conducting plate 34 to provide one electrical connection for the lamp. The other terminal wire makes contact with the cap 17 which is made of conducting material and thus, a second electrical connection for the lamp is provided.

A seating for the seal 14 is provided by indented portions of the wall of the cap 17. The cap 17 is formed with four indents 35 arranged in two pairs at diametrically opposed positions on the cap 17. The indents 35 are formed of a shape complementary to the shape of the seal 14 so that a face to face contact between the seal 14 and indents 35 is maintained when the envelope is seated in the cap.

The caps shown in the drawings are bayonet caps; however it is clear that other types of caps could be used, e.g. Edison screw caps, or 2 pin caps.

We claim:

1. A lamp comprising:

an envelope having a pinch seal at one end thereof;

at least one terminal wire sealed through and extending beyond said pinch seal;

a cap having a side wall disposed about said pinch seal;

indents formed in said side wall to form seating structures for said seal;

said terminal wires being connected to said cap whereby said seal is held against said seating structure and said envelope is prevented from moving axially relative to said cap.

2. An incandescent filament lamp comprising:

an envelope having a wedge-shaped pinch seal at one end thereof, the thin end end of the wedge being the end remote from the filament;

a pair of terminal wires sealed through said pinch seal in spaced apart relationship to one another and extending beyond said pinch seal;

a cap having a side wall disposed about said pinch seal;

indents formed in said side wall to form seating structures for said seal;

said indents abutting the sides of said wedge shaped pinch seal;

said terminal wires being connected to said cap whereby said seal is held against said seating structures and said envelope is prevented from moving axially relative to said cap.

3. A lamp as claimed in claim 1, wherein said pinch 4 seal tapers on at least one side from its centre towards 2,848,643 8/1958 Spataro 3l3-318 at least one edge. 2,984,810 5/1961 Kawate 313 318 X 4. A lamp as claimed in claim 1, wherein said seating 3,020,437 2/ 1962 Horan 313318 X structures have portions of a shape complementary to the shape of said pinch seal whereby a face to face f JAMES KALLAM, Prlmafy EXamlIlel' contact is maintained between said seal and said seating A, JAMES A i t t Examingr structures.

References Cited US. Cl. X.R. UNITED STATES PATENTS 313315; 339-145 2,433,373 12/1947 Krim 313318 X 10 

